I'm amazed at the number of people claiming that an extra 10-15 hp is even noticeable.

Try removing 15hp from your engine with a tune.

You will notice it.

A genuine 15hp is a lot. People often make the mistake of seeing it as a percentage however, 15hp is 15hp. It is enough for you to our drag anoher car with 15hp less especially once into the higher gears.